‘When it comes to building the human
brain, nature supplies the construction materials and nurture serves as the
architect that puts them together.’ Ronald
Kotulak[i]

There has always been an aura of mystery
about the inner workings of the brain. Over the years, experts have developed
numerous theories about the nature of intelligence and its relationship with two
powerful and sometimes conflicting forces: nurture and nature. Recently,
researchers have made more progress than ever before, and the mysteries of
intelligence have begun to unravel. For instance, scientists have now managed to
count the numbers of brain cells within specific areas of the brain. Even more
importantly, they have calculated the absolutely phenomenal number of
interconnections that are made amongst these cells as they communicate with one
another. In fact, scientists now have technology that allows them to look deep
inside the living, functioning brain. This enables them to directly observe
electro-chemical activity at the lowest levels, as thoughts and emotions are
developed and processed. As the mysteries of the brain are unravelling, many
long-held theories are being disproved and new ones developed.

What is becoming increasingly clear is
that the first few years of life are the most critical in terms of physical
brain development. While the long-term interaction between nature and nurture
determines the ultimate outcome, which is measurable in many different ways, the
most significant period for the actual wiring
of the brain is during the first few years of life. Typically, this process is
nearly complete by the age of twelve. We now also know that there are various
windows of opportunity during which the physical structures supporting certain
essential capabilities, such as language, hearing, and sight, are laid down.
Although the majority of these windows of opportunity occur between birth and
the age of three or four, nature gives a child’s brain a second chance between
the ages of about four and twelve. This means that an enormous responsibility
lies in the hands of parents and educators to ensure that a child’s brain
develops to its fullest potential.

At the micro level, the human brain
consists of about one hundred billion nerve cells, called neurons. These neurons can be
thought of as very simple data processors, which work together to solve a
particular problem as it is presented to the brain. Whilst individual neurons are far less
capable than even a rickety old computer from decades ago, the human brain is
still able to easily perform tasks that the largest, most expensive computers
today find impossible to accomplish. Some everyday examples of these tasks
include understanding spoken human language, identifying objects by sight,
sound, smell, touch, and taste, and writing and understanding literature. Other
examples are the ability to feel and respond to emotions, and to physically
express these emotions through poetry, music, and art.

The magic behind the brain’s power to
handle these and other complex tasks is that the billions of neurons work
together in concert, attacking problems in a massively parallel effort, by
breaking them up into many thousands or millions of smaller pieces and then
working on all those pieces at the same time. In contrast, computer processors
today typically attack problems sequentially, one piece at a time, and
accumulate the results until all of the pieces have been resolved. For the types
of tasks described above, the computer’s method is far less efficient than the
brain’s. In other words, the real power of the human brain lies in its ability
to orchestrate the activities of billions of individual neurons working
together, and the human brain can be likened to a symphony conductor.

Individual neurons operate at speeds measured only in the tens or hundreds of
cycles per second, which are called Hertz. By contrast, 1970s-era processors
operated at several million Hertz, whilst the latest members of Intel
Corporation’s Pentium family of processors operate at several billion Hertz. Yet
the human brain can still perform functions that are impossible for the most
sophisticated computer – because it can orchestrate billions of neurons to work
simultaneously on one task.

Because the role of neurons is to
process and then communicate vast amounts of information amongst themselves,
they require a physical means to transmit and receive data to and from the other
neurons. To support this communication, neurons develop dendrites for transmitting
information and axons
for receiving information from other neurons. As patterns of thought are first
initiated and subsequently repeated, the participating neurons continually
process and communicate. In doing so, they build stronger and more direct
dendrite-to-axon pathways or connections – called
synapses - to the other neurons that are
participating in the task. In other words, with repeated stimulation, these
connections become ever stronger and more established, and the brain has in
effect ‘learned’ how to solve that particular problem. At this point, the brain
is ready to undertake further learning. Interestingly, those neurons that do not
generate synapses quite literally die off, so the old saying ‘use it or lose it’
could not be more true.

At the macro level, the brain can be
thought of in three parts: the brain stem,
the limbic system and
the cerebral cortex.
These parts of the brain are divided again into specific areas, each with an
individual and complex role to play. Some areas process information gleaned from
the senses, whilst others process different aspects of our emotional responses.
Some are responsible for laying down certain types of memory, whilst others help
us to ‘read’ cues from other people and make appropriate emotional and physical
responses.

In order to make sense of the world,
however, these individual, specialized areas of the brain must be able to
communicate effectively with each other. In other words, the brain operates
similarly at the macro/regional level as it does at the micro/neural level,
relying on efficient communication amongst the regions to quickly resolve a
task. To illustrate this point, all of us have at one time or another used our
recollections of certain sights, sounds or smells to help us locate a specific,
long forgotten memory. Perhaps the smell of a particular curry dish, for
example, brings back memories of a joyous family gathering years ago, which
celebrated some remarkable academic achievement. You remember how happy and
proud you felt, wishing that night would never end.

In locating this memory, your brain has
used the information gathered by the olfactory nerves in the nose to match a
unique pattern that it has stored identifying the smell of the curry dish. The
patterns of other smells may have matched to one extent or another, but that
specific curry smell matched most closely. The neurons and synapses representing
this pattern then provided a map to the location in long-term memory of the
pattern representing the family gathering. This memory then triggers those same
happy and proud feelings, which you experience once again. As you can see from
this, various sections of the brain may indeed have specialized functions, but
they must still work together in order to provide what we somewhat loosely term
‘intelligence’.

Although the sections of the brain are
highly specialized, there is a degree of flexibility built into it. Until very
recently, it was thought that the functions of the various areas of the brain
were pre-programmed and inflexible, and that damage to one area of the brain
caused, for example, by a stroke, would lead to irreparable loss of function
throughout. The latest research, however, has shown that completely new wiring
can actually be created, and that some areas of the brain can take on entirely
new roles after physical damage has occurred to other sections. This flexibility
of the brain is known as plasticity.

If we envisage again the three primary
parts of the brain, the brain stem isphysically the lower part of the brain, which connects to the
spinal cord. It is often called the reptilian brain, as it was quite
likely the first true brain structure which evolved in higher order animals.
Along with the cerebellum, the brain stem is primarily responsible for the
body’s survival systems: for regulating our life support mechanisms such as
heart rate and breathing, and for what is known as the ‘flight or fight’
response to perceived danger. Under stress, our basic survival instincts kick in
and we produce chemicals that put the body under heightened alert. During these
times of stress, higher order thinking becomes derailed, and, therefore,
learning cannot take place effectively. It is for this reason that ideal
learning environments are those that reduce a child’s stress level to its
absolute minimum.

Between the brain stem and the cerebral
cortex is the limbic system. This is sometimes referred to as the mid-brain. The limbic system
consists of several structures that manage our emotions and are responsible for
some aspects of memory. The lower structures of the limbic system control our
more basic and instinctive emotional responses, whilst the higher ones are
responsible for making a more intellectual response to these emotions. For
example, if you were to hear an unfair criticism of your work, the lower areas
of the limbic system would deal with your more spontaneous responses such as
blushing or shaking, whilst the higher areas would process the cultural and
social issues that might help you to compose your expressions and make a
measured response to your critic. This makes sense, as the higher parts of the
limbic system are in closer contact with the cerebral cortex, where the most
sophisticated thought processes take place.

The cerebral cortex is the largest part
of the brain, sometimes referred to as the thinking brain. Most
high-level thinking processes take place here. It is physically separated into
two sides, rather like two halves of a walnut. Many theories exist about the
functions of these right and left hemispheres, and scientists are constantly
discovering more about the left-right relationship. Sometimes people describe
themselves as ‘left’ or ‘right’ brained. It is true that each individual has a
dominant side, but to use these descriptions is too simplistic. It really does
not matter which side is dominant, as the roles of the two hemispheres are
interdependent, and communication between the two is needed for even simple
tasks to be undertaken. For example, when listening to a piece of music, both
hemispheres are hard at work. The left hemisphere is responsible for identifying
familiar tunes, analysing and recognising sequences and rhythms, and identifying
changes in volume. Meanwhile, the right hemisphere works on the ‘bigger
picture’, whilst making pitch judgements and distinguishing between timbres.[ii]
For effective learning, the right and left hemispheres of the cerebral cortex
need to each do their own job and communicate effectively. The task of providing
for and managing this inter-hemisphere communication belongs to the corpus collosum, which is like
a super-highway through which messages travel.

Our understanding of the brain is
increasing continually, as scientists discover more about how we learn and
develop. As information becomes available about the functioning and capability
of the brain, we can become increasingly effective in helping children to learn
and develop to their full potential. What is perhaps startling is the fact that
altering a child’s environment and breadth of experiences can actually make a
radical difference to his or her IQ level at a later age:

‘Within a broad range set by one’s genes,
there is now increasing understanding that the environment can affect where you
are within that range…. You can’t make a 70 IQ person into a 120 IQ person, but
you can change their IQ measure in different ways, perhaps as much as 20 points
up or down, based on their environment.’ Dr. Frederick Goodwin,[iii]

Scientists are helping to inform our
practice more now than ever before. It is an exciting time to be involved with
children’s learning, and the adventure is only just beginning.